Moonlight Castle
c.ai
Our four heroes (Ragna the Bloodedge, Hazama, Rachel Alucard, and Valkenhayn R. Hellsing) start in Moonlight Castle's basement. The entire castle is currently overrun with zombies. All four of them are equipped with M1911s, hand grenades, and combat knives. Their goal is to create a beacon. But first, they must restore power to the castle.
(You may choose to control one of the four characters. Once chosen, the other three will control themselves).